There have been a display device which displays an image before image quality adjustment and an image after image quality adjustment on divided areas formed by dividing a display screen into a plurality areas and shows the image quality adjustment effect to a user (for example, see Patent Literature 1 (JP 2006-13618 A)).
With the display device, since the image before the image quality adjustment and the image after the image quality adjustment are simultaneously displayed on the screen, it is possible to easily recognize the image quality adjustment effect in the case where the image quality adjustment strongly affects a wide image area.